A cable modem termination system (CMTS) refers to hardware that is typically located in a cable company's master facility for receiving television signals for processing and distribution over a cable television system. This location is commonly referred to as a ‘headend.’ Most often, the CMTS is deployed at a cable company hubsite and is used to provide high speed data services, such as cable Internet and Voice-over-Internet Protocol (VoIP) to cable service subscribers.
To provide high speed data services (e.g., Internet, VoIP), the cable service provider connects its headend to the Internet via very high capacity data links, for example, through a network service provider. On the service subscriber side of the headend, the CMTS enables communication with subscribers' cable-equipped modems. While a CMTS is often capable of serving cable modem population sizes ranging from 4,000 cable modems to 150,000 or more, a particular headend can include multiple CMTSs so as to effectively service the cable modem population served by that headend.
A CMTS can be described as a switch or router having Ethernet-type connections on one side and coax radio frequency (RF) interfaces on the other. The Ethernet-type connections are used to bridge or route Internet traffic while the coax RF interfaces are employed to carry RF signals to and from the subscriber's cable modem. CMTSs typically only carry IP (Internet Protocol) traffic which is traffic specifically destined for the cable modem from the Internet, known as downstream traffic. Upstream data, or data from cable modems to the headend or Internet, is typically carried in Ethernet frames.
CMTS boxes are getting smaller while the physical plant ports are growing. Conventionally, the standard coaxial cable interface in the industry is the F-connector with RG-59 or RG-6 cable connectivity. Unfortunately, these conventional architectures are not maintainable in high density designs due to cable diameter, required access for F-connector installation, and cable bend radius.
Somewhat recent developments have been directed to cabling techniques that allow for higher densities in small form factors. For instance, one development was a system to fixture 1-10RF coaxial MCX type connectors and to provide driving and aligning features to connect to a mating LC (linecard) side connector.
One limitation of these conventional systems is that an external extraction tool had to be used to remove connectors from the header. This tool was required as the connector was retained within the header using a spring (or retaining ring) that contracts and expands over a lip. Additionally, in order to insert the extraction tool, the header must break all 10 RF connections and be removed from the LC in order to access the front of the header. In other words, the removal tool had to be inserted from the front end of the header thereby requiring that all connections must be broken. This requirement to break all connections limits the troubleshooting and reconfiguration capabilities when the cable plant is live.